Vacuum arc vapor deposition apparatus and vacuum arc vapor deposition method

ABSTRACT

A vacuum arc vapor deposition apparatus includes a plurality of magnetic coils for guiding a plasma produced by a vacuum arc evaporating source to the vicinity of a substrate in a film forming chamber by use of a deflection magnetic field. The vacuum arc vapor deposition apparatus further includes a coil power source for reversing a coil current to be fed to the magnetic coils, and a control unit for controlling the coil power source to reverse the flowing direction of the coil current.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a vacuum arc vapor deposition apparatusand a vacuum arc vapor deposition method used for forming a thin film ofexcellent lubricating property and hardness on such a substrate as anautomobile part, machine part, machine tool, and metal mold, whichincludes a magnetic coil for guiding a plasma produced by a vacuum arcevaporating source to the vicinity of the substrate. More particularly,the invention relates to a vacuum arc vapor deposition apparatus forpreventing degradation of the uniformity of a thickness distribution ona surface of the substrate, which is caused by the drift of the plasmain a magnetic field developed by the magnetic coil.

2. Description of the Related Art

A vacuum arc vapor deposition apparatus forms a film (thin film) on asubstrate by using a vacuum arc evaporating source which vaporizes acathode by vacuum arc discharge to produce a plasma containing a cathodematerial. The vacuum arc vapor deposition apparatus is advantageous inthat a film forming rate is high and highly productive.

The cathode material vaporized from the cathode of the vacuum arcevaporating source contains macro particles (called droplets) of severalμm or larger in addition to micro particles suitable for film formation.The macro particles fly to and attach onto the surface of the substrate,possibly damaging the adhesion property and smoothness (surfaceroughness) of the film.

To solve the above problems, the following two techniques are alreadyproposed: 1) technique for transporting the plasma to the substrateafter the macro particles are removed from the plasma by the utilizationof a deflection magnetic field (e.g., Japanese Patent UnexaminedPublication No. 2001-3160), and 2) technique to make the macro particlesfine by converging the plasma by the magnetic field to increase densityof the plasma (e.g., Japanese Patent Unexamined Publication No.2000-34561).

FIG. 10 is a cross sectional view showing a vacuum arc vapor depositionapparatus which uses the technique 1) above. The vacuum arc vapordeposition apparatus includes a film forming chamber (or vacuum chamber)2 which is vacuum discharged by a vacuum discharging apparatus (notshown). A holder 8 for holding a substrate 6 on which a film is formedis located in the film forming chamber.

In this example, a gas 4, such as inactive gas or reaction gas, isintroduced from a gas source (not shown) into the film forming chamber2.

Abias voltage V_(B) of −50V to −500V, for example, is applied from abias power source 10 to the holder 8 and the substrate 6.

The film forming chamber 2 is connected to a vacuum arc evaporatingsource 12 through a pipe 28 (deflection pipe) bent about 90° in thisexample.

The vacuum arc evaporating source 12 includes a cathode 14 mounted on anend plate 29 of the pipe 28 with an insulating material 20 insertedthere between. The cathode 14 is vaporized through vacuum arc dischargeoccurring between the cathode 14 and the pipe 28 serving also as ananode to produce a plasma 18 containing a cathode material 16. An anodeelectrode may be individually provided. Here, the “cathode material”means material forming the cathode 14. An arc discharging voltage isapplied from an arc power source 22 to between the cathode 14 and thepipe 28. The vacuum arc evaporating source 12 includes a known triggermechanism, a water cooling mechanism and the like. Those mechanisms arenot illustrated in the specification, for simplicity.

A plurality of magnetic coils 24 are provided around an outer peripheryof the pipe 28. The magnetic coils generate a magnetic field fordeflecting the plasma 18 produced by the vacuum arc evaporating source12, and guides (transports) the plasma 18 to the vicinity of thesubstrate 6 in the film forming chamber 2. Some of magnetic field lines26 generated by the magnetic coils 24 are roughly illustrated in thefigure, and as shown, those magnetic field lines extend substantiallyalong an inner surface of the pipe 28. Those magnetic coils 24 areconnected in series, and fed with a coil current I_(c) for generatingthe magnetic field from a coil power source 30.

The plasma 18 produced by the vacuum arc evaporating source 12 is bentto substantially along the magnetic field lines 26 and transported tothe substrate 6. The macroparticles emitted from the cathode 14 areelectrically neutral or negatively charged in the plasma 18. A mass ofthe macro particle is considerably large. Accordingly, those particlesgo straight irrespective of the magnetic field, and hit the inner wallof the bent pipe 28 and hence fail to reach the substrate 6. As aresult, the plasma 18 little containing the macro particles is led tothe vicinity of the substrate 6. Thus, it is prevented that the macroparticles attach to the substrate 6. The apparatus which has themagnetic coils 24, pipe 28 and coil power source 30 (coil power source40 in FIG. 1) as mentioned above is also called a magnetic filter whereattention is put on the macro-particle removing function.

Ions (i.e., ionized cathode material 16) in the plasma 18 thustransported to near the substrate 6 are attracted to the substrate 6under the bias voltage V_(B) and the like, and deposited on the surfaceof the substrate to form a thin film on the substrate. When a reactiongas which reacts with the cathode material 16 to form a chemicalcompound is used for the gas 4, a compound thin film may be formed.

When an electron is transported in a uniform magnetic field, as wellknown, the electron makes a gyrating movement such that it winds roundthe magnetic field lines, under Lorentz forces given by the followingequation 1. In the equation, q is a charge, v is an electron velocity,and B is a flux density (The same rule applies correspondingly to thedescription to follow.).

F=qvB  [Equation 1]

Accordingly, in a uniform magnetic field, electrons emitted from twopositions P and Q shown in FIG. 11 move along magnetic field lines 26uniformly distributed, reach the substrate 6, and are incident onpositions near positions P₁ and Q₁ corresponding to the positions P andQ.

Actually, a magnetic field developed by the magnetic coils 24 is notuniform and has gradients of a magnetic field without exception. Fordrift of charged particles, such as electrons, in a magnetic fieldhaving gradients, reference is made to “Newest Plasma ProductionTechnique”, by Yoshinobu Kawai, published by IPC corporation on Aug. 5,1991, pages 12 to 21. As described, the charged particle drifts at adrift velocity V_(D) given by the following equation 2. In the equation,μ is magnetic permeability, ∇B is a gradient (vector) of the magneticfield, and Bv is a magnetic field (vector), and other things are thesame as mentioned above. ∇ is a nabla or Hamiltonian operator.

V _(D)=−μ(∇B×Bv)/(qB ²)  [Equation 2]

The gradient of the magnetic field will be discussed by using anapparatus which transports the plasma 18 by use of the deflectionmagnetic field as shown in FIG. 10 (or FIG. 1 to be described later).

A case where the magnetic coil 24 and the pipe 28 are circular in crosssection is shown in FIGS. 12 to 18. In FIGS. 12 to 15, the cathodes 14 aand 14 b are simply represented by two positions “P” and “Q” (the samething is correspondingly applied to the illustrations of FIGS. 19 to 21to be described later). In FIGS. 16 to 18, the cathodes 14 a and 14 bare specifically illustrated (the same thing is correspondingly appliedto the illustrations of FIGS. 22 and 23 to be described later and FIGS.2 to 7).

In this case, the nature of the circular magnetic coils 24 gives themagnetic field in the pipe 28 such a gradient ∇ B as shown in FIG. 14that, an intensity of the magnetic field is lowest at the center 28 a ofthe pipe inside, and gradually increases toward the outside. In a casewhere a plurality of magnetic coils 24 are disposed while being bent asshown in FIG. 10, for example, the lowest intensity of the magneticfield is located at a position somewhat outwardly shifted from thecenter 28 a, actually.

Accordingly, as shown in FIGS. 12 and 13, electrons 32 a and 32 bemitted from the two positions P and Q drift at a drift velocity V_(D)in the circumferential direction (FIG. 15) by the gradient ∇B of themagnetic field (FIG. 14), as defined in the equation 2. Therefore, theelectrons land on the substrate 6 at positions shifted in thecircumferential direction. The same thing is true for the ions, andhence the plasma drifts, while being shifted in the circumferentialdirection.

In a case of FIGS. 16 and 17 where two vacuum arc evaporating sources 12are vertically spaced from each other and arranged along the z-axis,plasma 18 produced by the cathodes 14 a and 14 b reaches the substrate 6while drifting in the circumferential direction. A density distributionof each the plasma produced by the cathodes 14 a and 14 b is usuallydepicted in a shape of an outward curve; the density is highest at thecenter of the plasma in cross section and gradually decreases toward itsfringe. Accordingly, peaks 36 a and 36 b and fringes 38 a and 38 b of afilm thickness distribution (viz., a film forming velocity distribution)appear on the surface of the substrate 6 as shown in a FIG. 18 instance.As shown, those peaks and fringes are located at positions shifted inthe circumferential direction from positions 34 a and 34 b correspondingto the cathodes 14 a and 14 b.

A case where the magnetic coils 24 and the pipe 28 are rectangular intheir cross section is illustrated in FIGS. 19 to 23.

A magnetic field within the pipe 28 has such a gradient ∇B as shown inFIG. 20 that an intensity of the magnetic field is lowest at a part 28 bslightly closer to the outside than the center 28 a and graduallyincreases toward the outside. The gradient ∇B depends on the nature ofthe rectangular magnetic coils 24 and the arrangement of the pluralityof magnetic coils 24 arranged while being bent as shown in FIG. 10 andthe like.

As shown in FIGS. 12 and 19, electrons 32 a and 32 b emitted from twopositions P and Q drift at a drift velocity V_(D,) as defined in theequation 2 (FIG. 21), in a downward and oblique direction, which is theresultant of the downward direction and the lateral direction, by thegradient ∇B of the magnetic field 8 (FIG. 20).

In a case of FIGS. 16 and 22 where two vacuum arc evaporating sources 12are vertically spaced from each other and arranged along the z-axis,plasma 18 produced by the cathodes 14 a and 14 b reaches the substrate 6while drifting in the downward and oblique direction. Accordingly, peaks36 a and 36 b and fringes 38 a and 38 b of a film thickness distributionappear on the surface of the substrate 6 as shown in a FIG. 23 instance.As shown, the peaks 36 a and 36 b and fringes 38 a and 38 b are locatedat positions shifted in the downward and oblique direction frompositions 34 a and 34 b corresponding to the cathodes 14 a and 14 b.

Actually, a shift of the peak 36 a is different from that of the peak 36b. The lateral and downward shifts of the peak 36 b on the lower side(as viewed in the z-axis, the same will apply hereinafter.) are greaterthan that of the peak 36 a on the upper side. This fact was empiricallyconfirmed. The peaks 36 a and 36 b are shifted in directions in whichthe distance between them increases. Such an example is illustrated inFIG. 23. Where such shifts occur, film formation little occurs at thecentral part of the substrate 6. Further, the shifts become larger as adistance of the substrate 6 from the vacuum arc evaporating source 12increases.

Where the peaks 36 a and 36 b and the fringes 38 a and 38 b of the filmthickness distribution on the surface of the substrate 6 are shifted bythe gradient ∇B of the magnetic field, it is difficult to form a film onthe substrate 6 as desired. The shift will deteriorate the uniformity ofthe thickness distribution on the surface of the substrate 6. Whencomparing with a case where the magnetic coils 24 and the pipe 28 arecircular in cross section, in a case where the where the magnetic coils24 and the pipe 28 are rectangular in cross section, the peaks 36 a and36 b of the thickness distribution are shifted apart away from eachother, and the shifts of them become larger as a distance between thesubstrate 6 ad the vacuum arc evaporating source 12 increases.Accordingly, the uniformity of the thickness distribution on the surfaceof the substrate 6 is more deteriorated.

SUMMARY OF THE INVENTION

Accordingly, an object of the invention is to provide a vacuum arc vapordeposition apparatus and a vacuum arc vapor deposition method which canprevent degradation of the uniformity of a film thickness distributionon a surface of a substrate, which is caused by the drift of a plasma ina magnetic field developed by a magnetic coil.

In order to accomplish the object above, the following means areadopted. According to the present invention, there is provided a vacuumarc vapor deposition apparatus comprising: a film forming chambercontaining a substrate and being vacuum discharged; a vacuum arcevaporating source for producing a plasma containing a cathode materialby vaporizing a cathode by vacuum arc discharge; a magnetic coil forgenerating a magnetic field for deflecting or converging the plasmaproduced by the vacuum arc evaporating source, and guiding the plasma tothe vicinity of the substrate within the film forming chamber; a coilpower source for feeding a coil current for generating the magneticfield to the magnetic coil, the coil power source reversing a flowingdirection of the coil current fed to the magnetic coil; and a controlunit for controlling the coil power source to reverse the flowingdirection of the coil current fed to the magnetic coil.

The plasma is guided (transported) to the vicinity of the substrate bythe magnetic field developed by the magnetic coils before and after theflowing direction of the coil current fed to the magnetic coils isreversed. The reason for this is that so long as the magnetic fieldexists, the plasma is guided by the magnetic field.

When the flowing direction of the current fed to the magnetic coils isreversed, the gradient ∇B of the magnetic field remains unchanged, butthe direction of the vector of magnetic field B_(v) is reversed. As seenalso from the equation 2, the drift velocity V_(D) acting on the plasmato be transported is reversed in its direction.

The phenomenon, already stated, that the peak positions of the thicknessdistribution on the substrate surface are shifted by the drift of theplasma being under transportation, appears in the inverted state on thesubstrate surface when the flowing direction of the coil current isreversed. This inversion reduces the non-uniformity of the filmthickness distribution, thereby preventing the deterioration of theuniformity of the film thickness distribution on the substrate surface.The result is that a film maybe formed more uniformly over a broaderarea on the substrate.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram showing a vacuum arc vapor deposition apparatusaccording to the present invention;

FIG. 2 shows, in a view in the direction C—C in FIG. 1, an arrangementof cathodes in two vacuum arc evaporating sources increase where amagnetic coil and a pipe are rectangular in cross section;

FIG. 3 shows, in a view in the direction D—D in FIG. 1, drift directionsof electrons in a magnetic field by the magnetic coil in FIG. 1, beforethe coil current is reversed in its flowing direction, in a case where amagnetic coil and a pipe are rectangular in cross section;

FIG. 4 shows, in a view in the direction D—D in FIG. 1, drift directionsof electrons in a magnetic field by the magnetic coil in FIG. 1, afterthe coil current is reversed in its flowing direction, in a case where amagnetic coil and a pipe are rectangular in cross section;

FIG. 5 is a diagram showing film thickness distributions on a surface ofa film formed substrate by the cathodes in FIG. 2 before the coilcurrent is reversed in its flowing direction;

FIG. 6 is a diagram showing film thickness distributions on a surface ofa film formed substrate by the cathodes in FIG. 2 after the coil currentis reversed in its flowing direction;

FIG. 7 is a diagram showing film thickness distributions when the FIGS.5 and 6 distributions are superimposed one on the other;

FIG. 8 is a diagram showing a case where two thickness meters arelocated close to the periphery of the substrate;

FIG. 9 is a diagram showing a case where two ion current probes arelocated close to the periphery of the substrate;

FIG. 10 is a cross sectional view showing a vacuum arc vapor depositionapparatus in related art;

FIG. 11 is a diagram showing electron motions in a uniform magneticfield;

FIG. 12 is a diagram showing a portion of the magnetic coil of the FIGS.1 and 10 apparatus;

FIG. 13 is a diagram showing a cross section of the FIG. 12 structure asviewed in a direction C—C in a case where a magnetic coil and a pipe arecircular in cross section;

FIG. 14 is a diagram showing a gradation of a magnetic field in a crosssection of the FIG. 12 structure as viewed in a direction D—D in a casewhere a magnetic coil and a pipe are circular in cross section;

FIG. 15 is a diagram showing drift directions of electrons in a magneticfield developed by the FIG. 14 magnetic coil;

FIG. 16 is a diagram showing a structure of each of the FIGS. 1 and 10,which ranges from the cathode to the substrate;

FIG. 17 shows, in a view in the direction of C—C in FIG. 16, anarrangement of cathodes in a case where a magnetic coil and a pipe arecircular in cross section;

FIG. 18 is a diagram showing film thickness distributions on a surfaceof a film formed substrate, which are caused by the cathodes in FIG. 17;

FIG. 19 is a diagram showing a cross section of the FIG. 12 structure asviewed in a direction C—C in a case where a magnetic coil and a pipe arerectangular in cross section;

FIG. 20 is a diagram showing a gradation of a magnetic field in a crosssection of the FIG. 12 structure as viewed in a direction D—D in a casewhere a magnetic coil and a pipe are rectangular in cross section;

FIG. 21 is a diagram showing drift directions of electrons in a magneticfield developed by the FIG. 20 magnetic coil;

FIG. 22 shows, in a view in the direction of C—C in FIG. 16, anarrangement of cathodes in a case where a magnetic coil and a pipe arerectangular in cross section; and

FIG. 23 is a diagram showing film thickness distributions on a surfaceof a film formed substrate, which are caused by the cathodes in FIG. 22.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 is a diagram exemplarily showing a vacuum arc vapor depositionapparatus according to the present invention. FIG. 2 shows, in a view inthe direction C—C in FIG. 1, an arrangement of cathodes in two vacuumarc evaporating sources in a case where a magnetic coil and pipe arerectangular in cross section.

FIG. 2 is the same diagram as FIG. 22 described above. In the figures,like or same portions used in FIGS. 10 to 23 are designated by likereference numerals. Description will be given placing emphasis on thedifferences of the embodiment from the related art apparatus.

The vacuum arc vapor deposition apparatus shown in FIG. 1 comprises acoil power source 40 and a control unit 42. The coil power source 40 isused in place of the related art coil DC power source 30 and reversesthe flowing direction of coil current I_(c,) which flow through aplurality of magnetic coils 24,. The control unit 42 controls the coilpower source 40 to reverse the flowing direction of the coil currentI_(c) flowing through each magnetic coil 24.

The coil power source 40 may be a bipolar power source capable offeeding bipolar current or may be a combination of two DC power sources;one feeds a positive current, and the other feeds a negative current.

In the vacuum arc vapor deposition apparatus, two vacuum arc evaporatingsources 12 are arranged along the z-axis while being verticallyseparated from each other.

Each of magnetic coils 24 and the pipe 28 may be circular in crosssection as in the case described above. In the cases of FIGS. 2 to 7,the cross section configuration of them is rectangular.

The plasma 18 produced by the vacuum arc evaporating source 12 is guided(transported) to the vicinity of the substrate 6 in the film formingchamber 2 before and after the coil current I_(c) flowing through themagnetic coils 24 is reversed in its flowing direction. The reason forthis is that so long as the magnetic field exists, the plasma is guidedby the magnetic field.

When the coil current I_(c) flows through each magnetic coil 24 in theclockwise direction as viewed from the vacuum arc evaporating source 12,electrons 32 a and 32 b emitted from cathodes 14 a and 14 b of thevacuum arc evaporating sources 12 drift obliquely and downward at adrift velocity V_(D) as shown in FIG. 3. With the drift of theelectrons, the plasma 18, which is produced in the vicinity of thecathodes 14 a and 14 b and is transported by the magnetic field, driftin the same direction as of the electrons. As a result, peak positions36 a and 36 b and fringes 38 a and 38 b of a film thickness distributionof a thin film formed on the surface of the substrate 6 appear atpositions shifted obliquely and downward as shown in FIG. 5. FIGS. 3 and5 respectively correspond to FIGS. 21 and 23 mentioned above. The reasonwhy the drift velocity V_(D) and the thickness distribution are shiftedare as already described in detail.

When the flowing direction of the coil current I_(c) fed to magneticcoils 24 is reversed, i.e., in the counter clockwise direction as shownin FIG. 4, the gradient ∇B of the magnetic field developed by themagnetic coils 24 remains unchanged, but the direction of the vector ofmagnetic field B_(v) is reversed. As seen also from the equation 2, thedrift velocity V_(D) acting on the electrons 32 a and 32 bis reversed ina direction opposite to that in the FIG. 3 case. With the drift of theelectrons, the plasma 18, which is produced in the vicinity of thecathodes 14 a and 14 b and is transported by the magnetic field, driftsin the same direction as of the electrons drifting at drift velocityV_(D).

As a result, the phenomenon, already stated, that the peak positions 36a and 36 b and the fringes 38 a and 38 b of the thickness distributionon the substrate surface are shifted by the drift of the plasma beingunder transportation, appears in the inverted state, viz., by invertinga state of the FIGS. 3 and 5 case. Its state is shown in FIG. 6. Thepeaks 36 a and 36 bor the like of the film thickness distribution by thecathodes 14 a and 14 b are shifted obliquely and upward from thepositions 34 a and 34 b corresponding to the cathodes 14 a, 14 b while adistance between them increases.

By reversing the flowing direction of the coil current I_(c), thethickness distributions shown in FIGS. 5 and 6 are super imposed one onthe other into a film thickness distribution as shown in FIG. 7. Thus,peaks 36 a and 36 b and the fringes 38 a and 38 b of the film thicknessdistribution appear on the surface of the substrate 6 in a dispersingfashion. When a time t₁ that the coil current I_(c) flows clockwise isselected to be equal to a time t2 that the current flows counterclockwise, peaks whose magnitudes (film thickness) are substantiallyequal appear at four positions dispersley. With the dispersion of thepeak positions, non-uniformity of the thickness distribution on thesurface of the substrate 6 is reduced. Thus, deterioration of theuniformity of the film thickness distribution on the surface of thesubstrate 6 can be prevented by the drift of the plasma 18 in themagnetic field generated by the magnetic coils 24. As a result, a filmmay be formed uniformly on a broad area on the substrate 6.

The substrate 6 and the holder 8 holding it may be rotated about thecenter of the substrate 6 in, for example, a direction of an arrow “R”(or its reverse direction), as shown in FIGS. 1 and 7. By so doing, thenon-uniformity of the film thickness distribution is reduced through therotation of the substrate 6, so that the film thickness on the substrate6 is more uniform.

The control unit 42 controls the coil power source 40 to reverse theflowing direction of the coil current I_(c) after a predetermined timeelapses. The reversing operation may be performed one time; however, itis preferable to repeat the reversing operation at predetermined timeintervals. If so doing, the reducing of the non-uniformity of thethickness distribution caused by reversing the coil current I_(c)isrepeated, and hence, the thickness distribution is more uniform.

The time t1 of flowing the coil current I_(c) in the predetermineddirection and the time t₂ of flowing the same in the reverse directionmay be selected to be equal with each other. Those times may be selectedto be different so as to enhance the uniformity of the film thicknessdistribution by reducing the non-uniformity of the film thicknessdistribution in a more sophisticated manner.

It is preferable to repeat the reversing operation of the coil currentI_(c) direction at short time intervals. The reason for this is that itis possible to reduce the concentration of thermal stress on thesubstrate 6 by ions in the plasma 18 which are incident on thesubstrate, and hence the thermal stress concentration on the substrateis reduced. One of the preferable ways is to reverse the flowingdirection of the coil current I_(c) at a time interval, which is integertimes as long as a time taken for one rotation of the substrate 6. In aspecific example, where the time taken for one rotation of the substrate6 is 5 seconds, the flowing direction of the coil current I_(c) isreversed at a time interval of 10 seconds.

To more improve the uniformity of the film thickness distribution on thesurface of the substrate 6, the following thickness or ion currentdetecting unit may be employed.

In the vacuum arc vapor deposition device shown in FIG. 8, a pluralityof thickness meters 44 each for measuring a thickness of a film formedby the plasma 18 are disposed in the vicinity of the substrate 6.Specifically, in this instance, two thickness meters 44 are disposedclose to and above and below the substrate 6. The control unit 42performs the control for reversing the flowing direction of the coilcurrent I_(c) when a difference between film thickness values asmeasured by the two thickness meters 44 exceeds a predetermined value.

Where the thickness detecting unit is employed, the vacuum arc vapordeposition device performs the control for reversing the flowingdirection of the coil current I_(c) for reducing the non-uniformity ofthe thickness distribution on the surface of the substrate 6 whilemonitoring the film thickness on the surface of the film formedsubstrate 6 at plural positions close to the periphery of the substrate6. Accordingly, the uniformity of the thickness distribution on thesurface of the substrate 6 is more improved.

In the vacuum arc vapor deposition device shown in FIG. 9, a pluralityof ion current probes 46 are provided in the vicinity of the substrate6, for measuring ion currents II which flows when ions in the plasma 18are incident thereon. More specifically, in this instance, the two ioncurrent probes 46 are disposed above and below and near the substrate 6.Additionally, two current integrators 50 for integrating ion currentsI_(I) flowing through the ion current probes 46 are provided. The ioncurrent probes 46 may be kept at ground potential. To exactly measureion currents I_(I), it is preferable that a bias power source 48 isprovided, and it is-negatively biased, as in the instance. The controlunit 42 performs the control for reversing the flowing direction of thecoil current I_(c) when a difference between current values integratedby the two current integrators 50 exceeds a predetermined value.

The reason why a film is formed on the substrate 6 by guiding the plasma18 to the vicinity of the substrate 6, is that ions (ionized cathodematerial 16) in the plasma 18 are incident on the substrate 6. Acorrelation is present between the amount of the incident ions and thefilm thickness. The amount of the incident ions is measured by using theintegrated value of the ion currents I_(I).

Accordingly, by using the ion current detecting unit as mentioned above,the vacuum arc vapor deposition device performs the control forreversing the flowing direction of the coil current I_(c) for reducingthe non-uniformity of the amount of the incident ions while monitoringthe amount of incident ions on the substrate 6 at plural locations closeto the periphery of the substrate 6. This further improves theuniformity of the thickness distribution on the surface of the substrate6.

Also in the case where the magnetic coil 24 and the pipe 28 are circularin cross section, the plasma 18 drifts by the gradient ∇B of themagnetic field, thereby impairing the uniformity of the thicknessdistribution on the surface of the substrate 6, as described withreference to the FIGS. 13 to 15, 17, and 18. In this case, however, thedirection of the drift of the plasma 18 may be reversed by reversing theflowing direction of the coil current I_(c). With this, thenon-uniformity of the thickness distribution may be reduced.Specifically, the degradation of the uniformity of the thicknessdistribution on the surface of the substrate 6 is prevented by thereversed drift of the plasma 18 in the magnetic field developed by themagnetic coil 24.

In the embodiments mentioned above, a deflection magnetic field isdeveloped by the plurality of magnetic coils 24, and the plasma 18 isdeflected and transported. If required, the plasma 18 may be guide tothe vicinity of the substrate 6 by the magnetic field, while notdefected by the magnetic field. In this case, the macro particles aremade fine by converging the plasma 18 to increase the density of theplasma by one or a plurality of magnetic coils, as described above. Aslong as the plasma 18 is transported by using the magnetic fielddeveloped by the magnetic coil, the above-mentioned gradient ∇B of themagnetic field exists, and it causes the plasma 18 to drift in thepredetermined direction. This deteriorates the uniformity of thethickness distribution on the surface of the substrate 6. Similarly, inthis case, the direction of the drift of the plasma 18 may be reversedby reversing the flowing direction of the coil current I_(c).Accordingly, the non-uniformity of the thickness distribution may bereduced.

The present invention thus constructed has the following useful effects.

The vacuum arc vapor deposition device of the invention includes thecoil power source and the control unit. Accordingly, the flowingdirection of the coil current fed to the magnetic coils is reversed. Asa result, the phenomenon that the peak positions of the thicknessdistribution on the substrate surface are shifted by the drift of theplasma being under transportation, appears in the inverted state on thesubstrate surface when the coil current fed to the magnetic coils isreversed in its flowing direction. This reversion reduces thenon-uniformity of the film thickness distribution, thereby preventingthe deterioration of the uniformity of the film thickness distributionon the substrate surface. The result is that a film maybe formed moreuniformly over a broader area on the substrate.

When a plurality of vacuum arc evaporating sources are provided, and themagnetic coils generate a deflection magnetic field, the non-uniformityof the thickness distribution by the drift of the plasma is easy tooccur. In this case, the effect of improving the non-uniformity of thefilm thickness distribution is more remarkable when the coil powersource and the control unit are provided so that the flowing directionof the coil current fed to the magnetic coils is reversed.

In the vacuum arc vapor deposition device of the invention, the reducingoperation for the non-uniformity of the thickness distribution byreversing the flowing direction of the coil current may be carried outrepeatedly. Therefore, the uniformity of the thickness distribution isimproved.

The vacuum arc vapor deposition device of the invention may perform thecontrol for reversing the flowing direction of the coil current toreduce the non-uniformity of the thickness distribution while monitoringthe film thickness on the surface of the film formed substrate at aplurality of locations close to the periphery of the substrate.Accordingly, the uniformity of the thickness distribution on the surfaceof the substrate is improved.

The vacuum arc vapor deposition device of the invention may perform thecontrol for reversing the flowing direction of the coil current toreduce the non-uniformity of the amount of the incident ions whilemonitoring the amount of incident ions on the substrate in a pluralityof locations close to the periphery of the substrate. Accordingly, theuniformity of the thickness distribution on the surface of the substrateis improved.

What is claimed is:
 1. A vacuum arc vapor deposition apparatuscomprising: a film forming chamber containing substrate and being vacuumdischarged; a vacuum arc evaporating source for producing a plasmacontaining a cathode material by vaporizing a cathode by vacuum arcdischarge; a magnetic coil for generating a magnetic field fordeflecting or converging said plasma produced by said vacuum arcevaporating source, and guiding said plasma to the vicinity of saidsubstrate within said film forming chamber; a coil power source forfeeding a coil current for generating said magnetic field to saidmagnetic coil, said coil power source reversing a flowing direction ofthe coil current fed to said magnetic coil; a control unit forcontrolling said coil power source to reverse the flowing direction ofthe coil current fed to said magnetic coil; a plurality of thicknessdetecting units, disposed in the vicinity of said substrate, each formeasuring a thickness of a film formed by said plasma; and wherein saidcontrol unit performs the control for reversing the flowing direction ofthe coil current when a difference between film thickness values asmeasured by said plurality of thickness detecting units exceeds apredetermined value.
 2. The vacuum arc vapor deposition apparatusaccording to claim 1, wherein a plurality of vacuum arc evaporatingsources are provided, and said magnetic coil generates a deflectionmagnetic field for deflecting said plasma.
 3. The vacuum arc vapordeposition apparatus according to claim 1, wherein said control unitperforms a control for repeatedly reversing the flowing direction ofsaid coil current every predetermined time.
 4. The vacuum arc vapordeposition apparatus according to claim 1, wherein the substrate rotatesabout its center.
 5. The vacuum arc vapor deposition apparatus accordingto claim 4, wherein the flowing direction of the coil current isreversed at a time interval which is integer times as long as a timetaken for one rotation of the substrate.
 6. The vacuum arc vapordeposition apparatus according to claim 1, wherein said control unitcontrols a time of flowing the coil current in a predetermined directionand a time of flowing the coil current in a reverse direction to beequal with each other.
 7. A vacuum arc vapor deposition apparatuscomprising: a film forming chamber containing a substrate and beingvacuum discharged; a vacuum arc evaporating source for producing aplasma containing a cathode material by vaporizing a cathode by vacuumarc discharge; a magnetic coil for generating a magnetic field fordeflecting or converging said plasma produced by said vacuum arcevaporating source, and guiding said plasma to the vicinity of saidsubstrate within said film forming chamber; a coil power source forfeeding a coil current for generating said magnetic field to saidmagnetic coil, said coil power source reversing a flowing direction ofthe coil current fed to said magnetic coil; a control unit forcontrolling said coil power source to reverse the flowing direction ofthe coil current fed to said magnetic coil; a plurality of ion currentdetecting units, disposed in the vicinity of said substrate, formeasuring ion currents which flows when ions in said plasma are incidentthereon; and a plurality of current integrators for integrating ioncurrents flowing through said ion current detecting units, wherein saidcontrol unit performs the control for reversing the flowing direction ofthe coil current when a difference between current values integrated bysaid plurality of said current integrators exceeds a predeterminedvalue.
 8. The vacuum arc vapor deposition apparatus according to claim7, wherein a plurality of vacuum arc evaporating sources are provided,and said magnetic coil generates a deflection magnetic field fordeflecting said plasma.
 9. The vacuum arc vapor deposition apparatusaccording to claim 7, wherein said control unit performs a control forrepeatedly reversing the flowing direction of said coil current everypredetermined time.
 10. The vacuum arc vapor deposition apparatusaccording to claim 7, wherein the substrate rotates about its center.11. The vacuum arc vapor deposition apparatus according to claim 10,wherein the flowing direction of the coil current is reversed at a timeinterval which is integer times as long as a time taken for one rotationof the substrate.
 12. The vacuum arc vapor deposition apparatusaccording to claim 7, wherein said control unit controls a time offlowing the coil current in a predetermined direction and a time offlowing the coil current in a reverse direction to be equal with eachother.
 13. A vacuum arc vapor deposition apparatus comprising: a filmforming chamber containing a substrate and being vacuum discharged; aplurality of vacuum arc evaporating sources for producing a plasmacontaining a cathode material by vaporizing cathodes y vacuum arcdischarge; a magnetic coil provided over substantially the wholecircumference of a duct connecting the film forming chamber and theplurality of vacuum arc evaporating sources, the magnetic coilconfigured for generating a magnetic field for deflecting or convergingsaid plasma produced by said plurality of vacuum arc evaporatingsources, and guiding said plasma to the vicinity of said substratewithin said film forming chamber; a coil power source for feeding a coilcurrent for generating said magnetic field to said magnetic coil, saidcoil power source reversing a flowing direction of the coil current fedto said magnetic coil, the coil power source configured for feeding thecoil current to the magnetic coil so that the plasma in the duct driftsto cause the distribution of a film thickness on the substrate to besubstantially uniform; and a control unit for controlling said coilpower source to reverse the flowing direction of the coil current fed tosaid magnetic coil.